php header issue wont redirrect on duplicate function - header

Question

I have two nearly identical php functions both are functioning but for some reason the header will only run on the first one. I have no idea why this could be happening. I've seen some similarly titled post but none have solved or are the same as the problem I have so please don't remove this question. I've tried removing the closing php tag no help I've tried just about everything you could imagine but no cigar. the code is definitely running as echo's work at the end of the code so does exit(); but for some reason header just doesn't work. Any help would be greatly appreciated I will try anything. Also the reason I need this to work is so that when the page is refreshed it doesn't resubmit the form. I know this isn't much to go on so feel free to ask me questions.
function setComments($conn){
if (isset($_POST['commentsubmit'])) {
$uid = $_POST['uid'];
$date = $_POST['date'];
$message = mysqli_real_escape_string($conn, $_POST['message']);
$sql = "INSERT INTO comments (uid, date, message) values('$uid','$date', '$message')";
$result = mysqli_query($conn,$sql);
header("Location: videos.php");
}
}
duplicate code with alterations.
function setComments2($conn){
if (isset($_POST['commentsubmit2'])) {
$uid = $_POST['uid'];
$date = $_POST['date'];
$message = mysqli_real_escape_string($conn, $_POST['message']);
$sql = "INSERT INTO comments2 (uid, date, message) values('$uid','$date','$message')";
$result = mysqli_query($conn,$sql);
header("Location: home.html");
}
}

Answer 1

The header function calls were located AFTER other code.
PHP.net says this:
"Remember that header() must be called BEFORE any actual output is
sent, either by normal HTML tags, blank lines in a file, or from PHP.
It is a very common error to read code with include, or require,
functions, or another file access function, and have spaces or empty
lines that are output before header() is called. The same problem
exists when using a single PHP/HTML file."